/*
 * Copyright 2011 SWM Services GmbH.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package de.swm.commons.mobile.client.validation;

import com.google.gwt.user.client.ui.HasValue;



/**
 * Interface for validating a field's value.
 * @param <T> the type of the field Value.
 */
public interface IValidator<T> {

	/**
	 * Validates the fields value.
	 * 
	 * @param field
	 *            the field with his field value
	 * 
	 * @return <code>null</code> if validation passes, otherwise the error message
	 */
	public String validate(HasValue<T> field);

}
